This is just one video from a series of "nitpicking" videos from the YouTube channel Kaz's Japanese 101 & Eigonodo, run by Kaz, a native Japanese-speaking teacher of Japanese and English. The channel itself has been around for years and has all kinds of material for both Japanese and English learners, and this series includes ten or so videos of Kaz evaluating the spoken Japanese of (very) proficient non-native speakers.
In this particular video, Kaz watches a video made by YouTuber KemushiChan (a.k.a. Loretta Scott) pausing frequently to comment on her Japanese. As with all of the speakers in this series, Loretta's speaking level is so advanced that there are basically no grammar or vocabulary errors, so the majority of corrections concern pitch accent, vowel length, and double consonant sounds. Kaz also points out the particularly native-sounding moments in Loretta's spoken Japanese, which is helpful if you're looking for ways to make your own Japanese sound a bit more natural.
If you are an advanced speaker of Japanese, and you're looking to gain some more insight into the little mistakes you might be making, you're likely to find this video interesting. A lot of the corrections consist of Kaz simply repeating the incorrect pronunciation, followed by the correct version, and sometimes it would be nice to have some more explicit explanation of why it was wrong or unnatural. There is also a lot of English spoken, so it's not immersive listening practice, but for anyone interested in a more analytical and theoretical approach, these videos are worthwhile.
While his indirect style and occasional hesitation regarding the validity of his own corrections might bother some, this is itself an interesting insight into the many different versions of Japanese spoken in various parts of Japan. While this video series probably isn't for everyone, if you're an advanced learner who gets a kick out of the minute evaluation of language, Kaz's insightful comments and meticulous nitpicking might just help you to add the finishing touches to your own spoken Japanese.